Jeb Bush answers a question during an interview with Reuters in Peterborough, NH, on Oct. 13, 2015.
Brian Snyder—Reuters
By Justin Worland
October 18, 2015

Presidential candidate Jeb Bush said he has “grave doubts” about the ability of his GOP rival Donald Trump to be president in an interview on CNN’s State of the Union with Jake Tapper on Sunday.

“It looks as though he’s an actor playing a role of the candidate for president,” said Bush, arguing that Trump doesn’t understand foreign policy or the responsibilities of a president. “Across the spectrum of foreign policy, Mr. Trump talks about things as though he’s still on ‘The Apprentice.'”

In the interview, Bush specifically ridiculed Trump’s position that the U.S. should let the Islamic State of Iraq and Greater Syrua (ISIS) fight the Syrian government’s troops and then allow Russia to pick up the pieces. Bush described policy as “some kind of board game and not a serious approach.”

The comments come as Bush launches a new ad campaign ridiculing Trump’s foreign policy credentials. Despite the criticism, Trump continues to lead in both national and early voting state polls.

Write to Justin Worland at justin.worland@time.com.

Read More From TIME

EDIT POST